Agreement Among Three Methods of Intraoperative Core Temperature Monitoring: Nasopharyngeal Probe, TaiDoc TD-1261 Infrared Tympanic Thermometer, and 3M SpotOn™ Skin Sensor (TEMP-AGREE)

August 1, 2026 updated by: Thepakorn Sathitkarnmanee, Khon Kaen University

A Prospective Observational Method-Comparison Study of the Agreement Among Nasopharyngeal Temperature Probe, TaiDoc TD-1261 Infrared Tympanic Thermometer, and 3M SpotOn™ Zero-Heat-Flux Skin Sensor for Intraoperative Core Temperature Monitoring in Adult Patients Undergoing Elective Surgery Under General Anesthesia

Keeping a patient's body temperature normal during surgery is an important part of safe anesthetic care. When the body temperature drops below 36°C (called inadvertent perioperative hypothermia), patients face higher risks of bleeding, wound infection, heart problems, and a slower recovery. To prevent these complications, anesthesiologists monitor core body temperature continuously during surgery.

Three monitoring methods are commonly used in clinical practice: (1) a nasopharyngeal probe - a small soft sensor inserted through the nose and placed at the back of the throat, which provides continuous readings and is considered the gold standard; (2) an infrared tympanic thermometer (TaiDoc TD-1261) - a handheld device that measures ear temperature in about one second; and (3) the 3M SpotOn™ sensor - a non-invasive adhesive patch placed on the forehead that continuously estimates core temperature without requiring insertion into any body cavity.

Although all three methods are used interchangeably at Srinagarind Hospital, no study has directly compared all three simultaneously in the same patient to determine how well they agree with each other. If significant differences exist between methods, a clinician who switches from one device to another may unknowingly under-detect or over-estimate hypothermia.

This study will enroll 92 adult patients scheduled for elective surgery under general anesthesia at Srinagarind Hospital, Khon Kaen University. All three temperature sensors will be applied at the same time, and readings will be recorded simultaneously every 15 minutes throughout the operation. The main goal is to determine whether each device gives results close enough to the nasopharyngeal probe to be safely used as an alternative. The study is observational - no medications or procedures will be added to routine care.

Study Overview

Status

Not yet recruiting

Conditions

Detailed Description

Background: Inadvertent perioperative hypothermia (IPH), defined as a core body temperature < 36.0°C, affects 20-90% of patients undergoing general anesthesia and is associated with coagulopathy, surgical site infection, morbid cardiac events, and prolonged drug metabolism. Accurate intraoperative temperature monitoring is mandated by professional society guidelines.

Study design: Prospective, single-center, triple-method observational agreement study at Srinagarind Hospital, Khon Kaen University, Thailand. All three thermometry modalities are applied simultaneously in each participant. No intervention is assigned; temperature monitoring is additional to standard perioperative care.

Methods: After induction of general anesthesia and tracheal intubation, the nasopharyngeal (NP) probe (reference standard), TaiDoc TD-1261 infrared tympanic thermometer (test method 1), and 3M SpotOn™ zero-heat-flux forehead sensor (test method 2) are placed. Simultaneous temperature readings are recorded at 15-minute intervals from 15 minutes after induction until surgery end. For the TD-1261, two consecutive readings are taken at each time point and averaged; pinna retraction and fresh disposable probe cover are used at every measurement. The SpotOn™ sensor requires a 10-minute equilibration period before the first recorded value.

Statistical analysis: Primary analysis uses repeated-measures Bland-Altman analysis (Myles & Cui, 2007 framework) to estimate bias and limits of agreement (LoA) for each method pair against the NP probe. Pre-specified clinical acceptability criterion: LoA within ±0.5°C (Sessler, 2008). Variance of differences is decomposed into between-subject (σ²_B) and within-subject (σ²_W) components. Secondary analyses: proportional bias assessment, sensitivity/specificity for hypothermia detection (NP < 36.0°C), intraclass correlation coefficient (ICC, two-way mixed-effects model), and multivariable linear mixed-effects regression for clinical covariates. Sample size: 92 patients (Lu et al., 2016 method; 80% power; α = 0.05; SD of differences = 0.30°C for NP vs. TM; LoA acceptability threshold ±0.50°C; 15% dropout allowance).

This study provides the first institution-specific, population-specific evidence on temperature monitoring agreement in Thai surgical patients and constitutes the first published intraoperative validation of the TaiDoc TD-1261 infrared tympanic thermometer.

Study Type

Observational

Enrollment (Estimated)

270

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Thailand
      • Khon Kaen, Thailand, 40002
        • Faculty of Medicine, Khon Kaen University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Adult patients scheduled for elective surgery under general anesthesia with tracheal intubation at Srinagarind Hospital and Queen Sirikit Heart Center of the Northeast, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand, with expected surgical duration ≥ 60 minutes and ASA Physical Status I-III.

Description

Inclusion Criteria:

  • Age ≥ 18 years
  • We will include 3 independent groups of patients receiving general anesthesia with tracheal intubation:

Group 1: Cardiac surgery Group 2: Thoracic surgery Group 3: General surgery, including neurosurgery

  • Expected surgical duration ≥ 60 minutes
  • ASA Physical Status Classification I- III
  • Able to provide written informed consent

Exclusion Criteria:

  • Prior nasal surgery, nasal polyps, deviated nasal septum, or significant epistaxis history precluding safe nasopharyngeal probe insertion
  • Otitis media, tympanic membrane perforation, significant cerumen impaction, or external auditory canal deformity that would prevent reliable infrared tympanic temperature measurement
  • Facial or forehead skin lesions, burns, or known adhesive hypersensitivity at the planned 3M SpotOn™ application site, craniotomy, and head and neck surgery.
  • Baseline core temperature < 35.0°C or > 38.5°C at preoperative assessment
  • Planned use of neuraxial anesthesia as the primary or adjunct technique
  • Emergency procedures, pregnancy, or procedures involving deliberate hypothermia or cardiopulmonary bypass.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Surgical Patients - All Three Monitoring Methods
Adult patients (age ≥ 18 years) undergoing elective surgery under general anesthesia with tracheal intubation at Srinagarind Hospital and Queen Sirikit Heart Center of the Northeast, Khon Kaen University, with an expected surgical duration ≥ 60 minutes and ASA Physical Status I-III. All participants have all three temperature monitoring devices (NP probe, TaiDoc TD-1261 IR tympanic thermometer, and 3M SpotOn™ ZHF sensor) applied simultaneously following induction of anesthesia.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Limits of Agreement Between Each Test Method and the Nasopharyngeal Probe
Time Frame: From 15 minutes after anesthesia induction until end of surgery; measurements recorded at 15-minute intervals (estimated total observation window: 60-195 minutes per participant)
The 95% limits of agreement (LoA = Bias ± 1.96 × SD_total) between (i) the TaiDoc TD-1261 infrared tympanic thermometer and the nasopharyngeal probe, and (ii) the 3M SpotOn™ sensor and the nasopharyngeal probe, estimated by repeated-measures Bland-Altman analysis. Pre-specified clinical acceptability criterion: LoA must be contained within ±0.5°C with both 95% CI limits of the upper and lower LoA falling within this range.
From 15 minutes after anesthesia induction until end of surgery; measurements recorded at 15-minute intervals (estimated total observation window: 60-195 minutes per participant)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Systematic Bias (Mean Difference) of Each Test Method vs. NP Probe
Time Frame: From 15 minutes after anesthesia induction until surgery end (15-minute intervals)
Mean difference (°C) with 95% CI between each test method and the NP probe across all paired observations, estimated from the repeated-measures Bland-Altman model
From 15 minutes after anesthesia induction until surgery end (15-minute intervals)
Proportional Bias Assessment
Time Frame: From 15 minutes after anesthesia induction until surgery end
Linear regression of the difference (test - reference) on the mean of both methods, with cluster-robust standard errors; Pitman's test for correlation between sum and difference
From 15 minutes after anesthesia induction until surgery end
Sensitivity and Specificity for Hypothermia Detection
Time Frame: From 15 minutes after anesthesia induction until surgery end
Sensitivity, specificity, PPV, and NPV of each test method for detecting intraoperative hypothermia defined as NP temperature < 36.0°C, with AUROC estimated by DeLong's method
From 15 minutes after anesthesia induction until surgery end
Intraclass Correlation Coefficient
Time Frame: From 15 minutes after anesthesia induction until surgery end
ICC (two-way mixed-effects model, absolute agreement) with 95% CI for each method pair
From 15 minutes after anesthesia induction until surgery end
Percentage of Paired Measurements Within ±0.5°C
Time Frame: From 15 minutes after anesthesia induction until surgery end
Percentage of all paired simultaneous readings in which the test method falls within ±0.5°C of the simultaneous NP reference reading
From 15 minutes after anesthesia induction until surgery end
Clinical Covariate Association With Method Difference
Time Frame: Baseline characteristics collected before surgery; temperature data from 15 minutes post-induction until surgery end
Association between clinical covariates (age, sex, BMI, ASA status, surgical duration, anesthetic technique, active warming use, ambient OR temperature, baseline core temperature) and the absolute method difference, estimated by multivariable linear mixed-effects regression
Baseline characteristics collected before surgery; temperature data from 15 minutes post-induction until surgery end
Incidence of Device-Related Adverse Events
Time Frame: From device placement until surgery end
Rate of epistaxis (NP probe), aural discomfort or canal injury (TD-1261), and adhesive skin reaction (SpotOn™) during the monitoring period
From device placement until surgery end

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Khon Kaen University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

August 10, 2026

Primary Completion (Estimated)

February 28, 2027

Study Completion (Estimated)

April 30, 2027

Study Registration Dates

First Submitted

August 1, 2026

First Submitted That Met QC Criteria

August 1, 2026

First Posted (Actual)

August 6, 2026

Study Record Updates

Last Update Posted (Actual)

August 6, 2026

Last Update Submitted That Met QC Criteria

August 1, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • HE691250

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Deidentified individual participant temperature measurement data, baseline characteristics, and covariate data will be made available to qualified researchers following publication of the primary results in a peer-reviewed journal, subject to a data sharing agreement. Requests should be directed to the principal investigator.

IPD Sharing Time Frame

Starting 6 months after publication of the primary manuscript; available for 5 years thereafter

IPD Sharing Access Criteria

Qualified researchers submitting a methodologically sound research proposal. Requests will be reviewed by the Principal Investigator. A signed data sharing agreement is required. Data will be provided in de-identified format via secure file transfer.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Subscribe